Unable to ask question due to index is not built

[zjffdu]

I following the README instruction, but got this error when I ask question through UI.

Saved the state of the DB to /Users/jianfezhang/.adalflow/databases/AdalFlow.pkl
2025-02-10 10:00:06 - [data_pipeline.py:268:prepare_db_index] - total documents: 0
2025-02-10 10:00:06 - [data_pipeline.py:270:prepare_db_index] - total transformed documents: 0
len(self.transformed_docs): 0
2025-02-10 10:04:09.637 Uncaught app execution
Traceback (most recent call last):
  File "/Users/jianfezhang/github/metadata-repo/GithubChat/.venv/lib/python3.13/site-packages/streamlit/runtime/scriptrunner/exec_code.py", line 121, in exec_func_with_error_handling
    result = func()
  File "/Users/jianfezhang/github/metadata-repo/GithubChat/.venv/lib/python3.13/site-packages/streamlit/runtime/scriptrunner/script_runner.py", line 591, in code_to_exec
    exec(code, module.__dict__)
    ~~~~^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/jianfezhang/github/metadata-repo/GithubChat/app.py", line 99, in <module>
    response, docs = st.session_state.rag(query)
                     ~~~~~~~~~~~~~~~~~~~~^^^^^^^
  File "/Users/jianfezhang/github/metadata-repo/GithubChat/.venv/lib/python3.13/site-packages/adalflow/core/component.py", line 544, in __call__
    output = self.call(*args, **kwargs)
  File "/Users/jianfezhang/github/metadata-repo/GithubChat/src/rag.py", line 141, in call
    retrieved_documents = self.retriever(query)
  File "/Users/jianfezhang/github/metadata-repo/GithubChat/.venv/lib/python3.13/site-packages/adalflow/core/component.py", line 544, in __call__
    output = self.call(*args, **kwargs)
  File "/Users/jianfezhang/github/metadata-repo/GithubChat/.venv/lib/python3.13/site-packages/adalflow/components/retriever/faiss_retriever.py", line 335, in call
    self.indexed
AssertionError: Index is not built. Please build the index using build_index_from_documents